Blends of polyether sulfones and polyimides

Abstract

Blends of a polyether sulfone and the polyimide of the dianhydride sulfonyl bis(phthalic anhydride) ("SPAN") and the diamine 1,4-bis(p-aminocumyl)benzene ("BAP"). The blends will comprise from about 10 to about 90 wt % polyether sulfone, preferably greater than about 50 wt % polyether sulfone, based on the total weights of polyether sulfone and polyimide. The blends exhibit good toughness and improved thermal performance over polyether sulfone alone while remaining readily processable, and have good mechanical properties including unexpectedly high stiffness as determined by high tensile modulus values. Blends of this invention also are surprisingly miscible, defined as exhibiting a single Tg value.

We claim: 
     
       1. A composition comprising a blend of polyether sulfone and the polyimide of sulfonyl bis(phthalic anhydride) and 1,4-bis(p-aminocymyl)benzene, wherein said polyether sulfone does not contain a biphenyl unit. 
     
     
       2. The composition of claim 1 comprising greater than about 50 wt % of said polyether sulfone based on combined weights of polyether sulfone and polyimide. 
     
     
       3. The composition of claim 1 comprising from about 65 wt % to about 90 wt % of said polyether sulfone, based on combined weights of polyether sulfone and polyimide. 
     
     
       4. The composition of claim 1 comprising from about 70 wt % to about 90 wt % of said polyether sulfone, based on combined weights of polyether sulfone and polyimide. 
     
     
       5. A composition comprising a blend of from about 65 wt % to about 90 wt % of (a) an ether sulfone polymer of 4,4'-dichlorodiphenyl sulfone and at least one dihydric phenol selected from hydroquinone and 4,4'-dihydroxydiphenyl sulfone and, correspondingly, from about 35 wt % to about 10 wt % of (b) the polyimide of sulfonyl bis(phthalic anhydride) and 1,4-bis(p-aminocumyl) benzene, wherein said ether sulfone polymer does not contain a biphenyl unit. 
     
     
       6. The composition of claim 5 comprising from about 70 wt % to about 90 wt % of component (a) and from about 30 wt % to about 10 wt % of component (b). 
     
     
       7. The composition of claim 5 wherein component (a) is an ether sulfone polymer of 4,4'-dichlorodiphenyl sulfone and 4,4'-dihydroxydiphenyl sulfone. 
     
     
       8. The composition of claim 5 wherein component (a) is an ether sulfone polymer of 4,4'-dichlorodiphenyl sulfone, hydroquinone and 4,4'-dihydroxydiphenyl sulfone.